NFC antenna system for metalized devices

Abstract

An antenna system is described for implementation in devices enclosed in a metallic enclosure, where a small opening is introduced in the metallic enclosure and a magnetic field is generated external to the metallic enclosure for use in near field communication applications. An antenna structure is described that is internal to the metallic enclosure that generates a magnetic field on the axis of the opening in the metallic enclosure.

What is claimed is: 
     
       1. An antenna system comprising:
 a conductor in the form of a wire or planar trace wrapped or deposited on the outer surface of a non-metallic support to form a coil, wherein a first end of the coil coupled to a common ground and a second end of the coil coupled to a transceiver; 
 a first metallic enclosure enclosing said coil, the first metallic enclosure having a first end and a second end opposing the first end, the first end and the second opposing end containing no metallization and coincident with a first plane and a second plane forming the first end and the second end of said coil; 
 a ground plane forming the common ground; 
 the first metallic enclosure positioned in close proximity to the ground plane, and is electrically coupled to the ground plane; 
 the first end of said coil further coupled to the first metallic enclosure and/or the ground plane; and 
 said coil configured to operate at a first frequency. 
 
     
     
       2. The antenna system of claim,  1  wherein a volume of material within the inner region of said coil having material possessing dielectric properties and/or magnetic properties. 
     
     
       3. The antenna system of  claim 1 , wherein the transceiver is provides a radio frequency (RF) transmit signal to said coil which in turn generates a magnetic field directive in the axis of said coil and concentrated around the first opposing end of the first metallic enclosure. 
     
     
       4. The antenna system of  claim 1 , wherein the first metallic enclosure and ground plane are enclosed in a second metallic enclosure including an aperture aligned with the first end of the first metallic enclosure. 
     
     
       5. The antenna system of  claim 4 , wherein the aperture has a 3.5 mm circular diameter. 
     
     
       6. The antenna system of  claim 4 , wherein a slot is added above the opening in the second metallic enclosure. 
     
     
       7. The antenna system of  claim 1  further configured to operate at 13.56 MHz for use in NFC (Near Field Communication) applications. 
     
     
       8. The antenna system of  claim 6  further configured to operate at 13.56 MHz for use in NFC (Near Field Communication) applications. 
     
     
       9. The antenna system of  claim 1 , wherein the ground plane is coupled to a printed circuit board. 
     
     
       10. An antenna system comprising:
 a first conductor in the form of a wire or planar trace wrapped or deposited on the outer surface of a first non-metallic support to form a first coil, wherein a first end of the first coil coupled to a common ground and a second end of the first coil coupled to a transceiver; 
 a first metallic enclosure enclosing said first coil, the first metallic enclosure having a first end and a second end opposing the first end, the first end and the second opposing end containing no metallization and coincident with a first plane and a second plane forming the first end and the second end of said coil; 
 a ground plane forming the common ground; 
 a second conductor in the form of a wire or planar trace wrapped or deposited on the outer surface of a second non-metallic support to form a second coil, wherein a first end of the second coil coupled to the common ground and a second end of the second coil coupled to the transceiver; 
 a second metallic enclosure enclosing said second coil, the second metallic enclosure having a first end and a second end opposing the first end, the first end and the second opposing end containing no metallization and coincident with a first plane and a second plane forming the first end and the second end of said second coil; 
 the first metallic enclosure positioned in close proximity to the ground plane, and is electrically coupled to the ground plane; 
 the first end of said first coil further coupled to the first metallic enclosure and/or the ground plane; 
 said first coil configured to operate at a first radio frequency; 
 the second metallic enclosure positioned in close proximity to the ground plane at an opposing end of said ground plane opposing to the first metallic enclosure, the second metallic enclosure electrically coupled to the ground plane; 
 the first end of said second coil further coupled to the second metallic enclosure and/or the ground plane; 
 said second coil configured to operate at the first radio frequency; and 
 the first metallic enclosure, the second metallic enclosure, and the ground plane enclosed in a third metallic enclosure. 
 
     
     
       11. The antenna system of  claim 7 , wherein the third metallic enclosure includes an aperture aligned with the first end of the first metallic enclosure. 
     
     
       12. The antenna system of  claim 8 , wherein the aperture has a 3.5 mm circular diameter. 
     
     
       13. The antenna system of  claim 7 , wherein a volume of material within the inner region of said first coil possessing dielectric properties and/or magnetic properties. 
     
     
       14. The antenna system of  claim 7 , wherein a volume of material within the inner region of said second coil possessing dielectric properties and/or magnetic properties. 
     
     
       15. The antenna system of  claim 7 , wherein a volume of material within the inner region of said first coil, and a volume of material within the inner region of said second coil possessing dielectric properties and/or magnetic properties. 
     
     
       16. The antenna system of  claim 7 , wherein the transceiver is coupled to the said first and said second coils by way of two conductive paths or transmission lines. 
     
     
       17. The antenna system of  claim 7 , wherein a phase controller is coupled between the transceiver and said second coil, the phase controller capable of varying a phase length of a radio frequency path. 
     
     
       18. The antenna system of  claim 14 , wherein the phase length is altered to increase electromagnetic (EM) field strength directive in the axis of said first coil and concentrated around the aperture in the third metallic enclosure. 
     
     
       19. The antenna system of  claim 14 , wherein the antenna system positioned in an electromagnetic (EM) field, the antenna system receiving power directive in the axis of said first coil and concentrated around the aperture in the third metallic enclosure. 
     
     
       20. The antenna system of  claim 7  wherein a slot is added above the opening in the third metallic enclosure. 
     
     
       21. The antenna system of  claim 6 , wherein the ground plane is coupled to a printed circuit board. 
     
     
       22. An antenna system comprising:
 a conductor in the form of a wire or planar trace wrapped or deposited on the outer surface of a non-metallic support to form a coil, wherein a first end of the coil coupled to a common ground and a second end of the coil coupled to a transceiver; 
 a first metallic enclosure enclosing said coil, the first metallic enclosure having a first end and a second end opposing the first end, the first end and the second opposing end containing no metallization and coincident with a first plane and a second plane forming the first end and the second end of said coil; 
 a ground plane forming the common ground, wherein the ground plane is coupled to a printed circuit board; 
 the first metallic enclosure positioned in close proximity to the ground plane, and is electrically coupled to the ground plane; 
 the first end of said coil further coupled to the first metallic enclosure and/or the ground plane; 
 wherein the first metallic enclosure and the ground plane are enclosed in a second metallic enclosure including an aperture aligned with the first end of the first metallic enclosure; and 
 said coil configured to operate at a first frequency.